Short-term Plasmodium infections were induced in chimpanzees to obtain blood-stage parasites for (1) preparation of genomic libraries, (2) extraction of m-RNA for genetic engineering studies, (3) antigen for serologic tests, (4) infection of mosquitoes through membrane feeding to produce sporozoites for (a) genetic engineering studies, (b) production of monoclonal antibodies, and (c) to infect Aotus and Saimiri monkeys and to test the efficacy of experimental vaccines, and (5) production of immune sera. The following malarial parasites and animals were inoculated during the past year Plasmodium vivax - animals C-505, C-475 and C-515; Plasmodium malariae - animals C-382 and C-529. These studies will continue in support of the development of vaccines for human malarias.